Invoke ant from java, then return to java after an

Question

so far i have invoked ant script from java. Now the question is, is it possible to resume java execution after the termination of the ant build?

How do i do it?

Answer 1

Process p = Runtme.getRuntime.exec("ant mytarget");
p.waitFor();  // waits until process completes before continuing to next line
// continue Java program here

Answer 2

org.apache.tools.ant.Main's main() and startAnt() methods call the exit() method which in turn calls System.exit(code).

The solution (assuming you call one of those methods) is to sub-class org.apache.tools.ant.Main and override the exit() method

/**
 * This operation is expected to call {@link System#exit(int)}, which
 * is what the base version does.
 * However, it is possible to do something else.
 * @param exitCode code to exit with
 */
protected void exit(int exitCode) {
    System.exit(exitCode);
}

Answer 3

Check out the source of Ant's main class, org.apache.tools.ant.Main. You can try to invoke its main or start method directly, or copy some of its logic to your application. After those methods finish, your application should continue execution.

EDIT:

The answer by Paul Cager is correct, I somehow missed the fact that Ant's Main calls System.exit().

Another thing about the main/start/startAnt methods is that they expect the arguments as an array of strings. This can be handy, but it's not particularly typesafe or object-oriented. To invoke Ant for a given buildfile and target, you can use something like this:

public static void runAnt(String buildfile, String target) throws Exception {
    File buildFile = new File(buildfile);
    Exception error = null;
    org.apache.tools.ant.Project project = new org.apache.tools.ant.Project();
    try {
        project.addBuildListener(new org.apache.tools.ant.listener.Log4jListener());
        project.fireBuildStarted();
        project.init();
        project.setUserProperty(org.apache.tools.ant.MagicNames.ANT_FILE, buildFile.getAbsolutePath());
        org.apache.tools.ant.ProjectHelper.configureProject(project, buildFile);
        project.executeTarget(target);
    } catch (Exception e) {
        error = e;
        throw e;
    } finally {
        project.fireBuildFinished(error);
    }
}